This invention relates to apparatus for the recovery of sensible heat from molten slag discharged from metallurgical furnaces such as converters and blast furnaces.
Of a variety of schemes heretofore suggested and practiced for heat recovery from molten slag, two typical ones are disclosed in Japanese patent application Nos. 90932/1976 and 155448/1976 laid open to public inspection as Nos. 16031/1978 and 78995/1978, respectively. The former proposes the quenching of molten slag with an inert gas and the recovery of heat from the inert gas by means of a heat exchanger such as a cooler or boiler.
The latter application, on the other hand, teaches the slurrying of molten slag with water. After being pressurized to augment its sensible heat, the slurried slag is introduced into a cooler tank to provide saturated steam and heated water. The cooler tank has a heat exchanger mounted therein for heating pure water with the changer mounted therein for heating pure water with the heated water. Heat is thus recovered from the molten slag in the form of saturated steam.
Both prior art techniques have a common deficiency: they do not provide for the recovery of heat radiated from molten slag. The efficiency of these and like conventional systems is therefore not necessarily high. According to the second mentioned application, in particular, the pressure within the cooler tank sets a limit on recoverable heat, and mechanical limitations make it difficult to handle large quantities of slag at one time.